JP6674367B2 - Automotive fuel cell stack - Google Patents

Description

  The present invention relates to an in-vehicle fuel cell stack having a stack in which a plurality of power generation cells are stacked is housed in a stack case and provided with a ventilation mechanism for ventilating the inside of the stack case.

  For example, a polymer electrolyte fuel cell has an electrolyte membrane / electrode structure (MEA) in which an anode electrode is provided on one surface of an electrolyte membrane made of a polymer ion exchange membrane, and a cathode electrode is provided on the other surface. Is provided. The electrolyte membrane / electrode structure constitutes a power generation cell (unit cell) by being sandwiched between separators. Usually, a predetermined number of power generation cells are stacked to be mounted on a fuel cell vehicle, for example, as a vehicle-mounted fuel cell stack.

  2. Description of the Related Art In an on-vehicle fuel cell stack, a configuration is employed in which a stack in which a predetermined number of power generation cells are stacked is housed in a stack case. In this case, it is supposed that hydrogen gas leaks out of the stack case through gaps between the stacked bodies. Therefore, when the stacked body is stored in the stack case, hydrogen gas leaked from the stack case is accumulated. Therefore, it has been proposed to provide a ventilation mechanism that ventilates the inside of the stack case by introducing air from the outside into the stack case so that the concentration of hydrogen gas becomes equal to or lower than a certain concentration (for example, see Patent Document 1). ).

JP-A-2004-186029

  By the way, since the ventilation mechanism has an air inlet and a flow path communicating between the inside and the outside of the stack case, the air, such as water, dust, mud, pebbles, etc., is supplied from outside through the air inlet and the flow path of the ventilation mechanism. Foreign matter may enter the stack case.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide an in-vehicle fuel cell stack capable of suppressing foreign matters other than air from entering a stack case as much as possible. Aim.

In order to achieve the above object, according to the present invention, a power generation cell that generates power by an electrochemical reaction between a fuel gas and an oxidizing gas includes a plurality of stacked bodies, and the stacked bodies are housed in a stack case. An in-vehicle fuel cell stack, comprising: a ventilation mechanism that ventilates the inside of the stack case through a ventilation opening that opens into the stack case, wherein the ventilation mechanism is configured to introduce air for ventilation from outside. an inlet having an inlet member and an internal flow path is formed for communicating the ventilation openings and the air inlet, the internal channel may have a labyrinth flow path, said labyrinth flow path, characterized Rukoto is formed in a cylindrical shape along the direction of gravity.

  Preferably, the ventilation opening is provided at a lower portion of the stack case.

  It is preferable that the ventilation mechanism has a tube member having one end connected to the ventilation opening and the other end connected to the inlet member.

  It is preferable that the inlet member is disposed on an undercover of a vehicle on which the on-vehicle fuel cell stack is mounted, and the air inlet is opened on a lower surface of the vehicle.

  It is preferable that the cross-sectional area of the labyrinth flow path is equal to or larger than the cross-sectional area of the tube member over the entire length of the flow path.

  The air inlet is open downward, the inlet member has at least one barrier plate forming the labyrinth flow path, and an inner peripheral portion or an outer peripheral portion of the at least one barrier plate is downward. It is preferable to be inclined or protruded toward.

  The air inlet is open downward, the inlet member has a plurality of barriers forming the labyrinth flow path, and the plurality of barriers face the air inlet in opposition to the air inlet. It is preferable to have a first barrier portion disposed above the inlet, and a second barrier portion having an opening formed at a position above the first barrier portion facing the first barrier portion. .

  The air inlet may be open downward, and the inlet member may be provided with a plurality of drain holes around the air inlet and communicating the internal flow path and the outside of the inlet member. preferable.

  It is preferable that a mesh member is provided at the air inlet.

  The vehicle fuel cell stack of the present invention includes a ventilation mechanism for ventilating the inside of the stack case, and a labyrinth flow path is provided in an inlet member of the ventilation mechanism. For this reason, the inside of the stack case can be satisfactorily ventilated, and the hydrogen gas concentration in the stack case can be reduced to a certain concentration or less. Further, even when foreign substances such as water, dust, mud, and pebbles scatter toward the inlet member during traveling of the fuel cell vehicle, the foreign substances are prevented from entering the ventilation opening side by the labyrinth flow path. . Therefore, it is possible to suppress foreign matter from entering the stack case through the ventilation opening as much as possible.

FIG. 1 is a schematic perspective explanatory view of a front part of a fuel cell vehicle on which a vehicle-mounted fuel cell stack according to an embodiment of the present invention is mounted. FIG. 2 is an exploded perspective view of the fuel cell stack. It is a perspective sectional view of an inlet member. It is operation | movement explanatory drawing of an inlet member at the time of a small amount of water. It is operation | movement explanatory drawing of the inlet member at the time of a large amount of water. It is a graph which shows the relationship between time and a water level about the water level in an inlet member according to water volume. It is a perspective explanatory view from the bottom of the structure in which the mesh member was provided in the air inlet.

  Hereinafter, preferred embodiments of a vehicle fuel cell stack according to the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, a vehicle fuel cell stack 10 according to an embodiment of the present invention (hereinafter, referred to as “fuel cell stack 10”) is mounted on a fuel cell vehicle 12 such as a fuel cell electric vehicle, for example. The fuel cell vehicle 12 has a vehicle body 12a provided with a front wheel 11F and a rear wheel (not shown).

  A front box (motor room) 14 for mounting the fuel cell stack 10 is formed in front of the dashboard 16 on the front wheel 11F side of the vehicle body 12a. The fuel cell stack 10 can be mounted under the floor, a trunk lid, or the like, in addition to the front box 14.

  As shown in FIG. 2, the fuel cell stack 10 includes a stack 19 in which a plurality of power generation cells 18 are stacked, and a stack case 20 that stores the stack 19. The plurality of power generation cells 18 are stacked in the vehicle width direction (the direction of arrow B), which is a horizontal direction, with the power generation surface standing. At one end of the power generation cell 18 in the stacking direction, a first terminal plate 22a, a first insulating plate 24a, and a first end plate 26a are sequentially arranged outward.

  At the other end of the power generation cell 18 in the stacking direction, a second terminal plate 22b, a second insulating plate 24b, and a second end plate 26b are sequentially disposed outward. At both ends in the vehicle width direction of the fuel cell stack 10, a first end plate 26a and a second end plate 26b are arranged.

  The first end plate 26a forms one wall of the rectangular parallelepiped stack case 20, and the second end plate 26b forms a wall of the stack case 20 opposite to the first end plate 26a. I do. The fuel cell stack 10 is fixed to the vehicle frame via mount members (not shown) provided on the first end plate 26a and the second end plate 26b.

  Each power generation cell 18 includes an electrolyte membrane / electrode structure (MEA) in which an electrolyte membrane such as a solid polymer electrolyte membrane is sandwiched between a pair of electrodes (anode electrode and cathode electrode); It has a metal or carbon separator laminated on both sides. Note that each power generation cell 18 may have a configuration in which two electrolyte membrane / electrode structures and three separators are alternately stacked.

  The oxidizing gas inlet communication hole, the cooling medium inlet communication hole, and the fuel gas outlet communication hole are individually connected to one edge of the power generation cell 18 in the direction of arrow A in the stacking direction (direction of arrow B). They are arranged in the C direction (vertical direction).

  The oxidizing gas inlet communication hole supplies an oxidizing gas (for example, an oxygen-containing gas) to an oxidizing gas flow path formed on the cathode electrode side in the power generation cell 18. The cooling medium inlet communication hole supplies a cooling medium (for example, water) to a cooling medium formed between the adjacent power generation cells 18. The fuel gas outlet communication hole discharges a fuel gas (for example, a hydrogen-containing gas).

  The other end of the power generation cell 18 in the direction of arrow A is individually communicated in the direction of arrow B, and a fuel gas inlet communication hole, a cooling medium outlet communication hole, and an oxidizing gas outlet communication hole are formed in the arrow C direction. It is provided in an array. The fuel gas inlet communication hole supplies fuel gas to a fuel gas flow path formed on the anode electrode side in the power generation cell 18. The cooling medium outlet communication hole communicates with the cooling medium flow path, and discharges the cooling medium. The oxidizing gas outlet communication hole communicates with the oxidizing gas flow path, and discharges the oxidizing gas.

  An oxidizing gas supply manifold 30a communicating with the oxidizing gas inlet communication hole and an oxidizing gas discharge manifold 30b communicating with the oxidizing gas outlet communication hole are provided at one diagonal position of the first end plate 26a. . At the other diagonal position of the first end plate 26a, a fuel gas supply manifold 32a communicating with the fuel gas inlet communication hole and a fuel gas discharge manifold 32b communicating with the fuel gas outlet communication hole are provided.

  The second end plate 26b is provided with a cooling medium supply manifold 33a communicating with the cooling medium inlet communication hole and a cooling medium discharge manifold 33b communicating with the cooling medium outlet communication hole.

  The stack case 20 includes a front side panel 20Fr, a rear side panel 20Rr, an upper panel 20Up, and a lower panel 20Lw, and includes the above-described first end plate 26a and second end plate 26b. Each panel is fixed to the first end plate 26a and the second end plate 26b by screws 34. Adjacent panels are mutually fixed by screws 34.

  In the upper panel 20Up, exhaust openings 36a, 36b communicating with the inside of the stack case 20 to the outside are formed at one diagonal position, and exhaust openings communicating the inside of the stack case 20 to the outside at the other diagonal position. Parts 36c and 36d are formed. The exhaust openings 36a and 36c are provided on both front sides (in the direction of the arrow Af) of the stack case 20, and are disposed vertically above the fuel gas inlet communication hole.

  In FIG. 1, exhaust ducts 38a and 38d are connected to the exhaust openings 36a and 36d. The exhaust ducts 38a and 38d join at the right exhaust duct 40R. The exit of the right exhaust duct 40R opens to the right fender 42R of the vehicle body 12a. Exhaust ducts 38b and 38c are connected to the exhaust openings 36b and 36c. The exhaust ducts 38b and 38c join at the left exhaust duct 40L. The outlet of the left side exhaust duct 40L opens to the left side fender portion 42L of the vehicle body 12a.

  As shown in FIG. 2, the lower panel 20 </ b> Lw, which is the lower part of the stack case 20, is provided with a ventilation opening 44 communicating between the inside and the outside of the stack case 20. The ventilation opening 44 is a hole penetrating the lower panel 20Lw in the thickness direction (vertical direction). In FIG. 2, the ventilation opening 44 is provided on the vehicle front side of the lower panel 20Lw. The ventilation opening 44 may be provided on the vehicle rear side of the lower panel 20Lw, or may be provided on the center side of the lower panel 20Lw in the vehicle front-rear direction.

  In FIG. 2, ventilation openings 44 are provided on one side (left side) and the other side (right side) in the vehicle width direction, respectively. Note that the ventilation opening 44 may be provided on the center side in the vehicle width direction. Three or more ventilation openings 44 may be provided, or only one ventilation opening may be provided.

  As shown in FIG. 1, the fuel cell stack 10 further includes a ventilation mechanism 50 for ventilating the inside of the stack case 20. The ventilation mechanism 50 has a ventilation opening 44 that opens into the stack case 20. As described above, the ventilation opening 44 is provided in the lower panel 20Lw that constitutes the lower part of the stack case 20, and the ventilation mechanism 50 ventilates the inside of the stack case 20 through the ventilation opening 44.

  In the present embodiment, the ventilation mechanism 50 includes an inlet member 52 that constitutes a part for introducing air from outside, and a tube member 54 that connects the stack case 20 and the inlet member 52. In the fuel cell stack 10, it is preferable that a plurality of ventilation mechanisms 50 are provided. In FIG. 1, two ventilation mechanisms 50 are arranged at intervals in the vehicle width direction (left-right direction) (arrow B direction). The plurality of ventilation mechanisms 50 may be arranged at intervals in the vehicle front-rear direction. Only one ventilation mechanism 50 may be provided.

  In FIG. 1, the inlet member 52 is arranged on the vehicle front side (on the arrow Af direction side) with respect to the stack case 20. In addition, the inlet member 52 may be arranged on the vehicle rear side (the direction of the arrow Ab) with respect to the stack case 20, or the inlet member 52 may be arranged at a position overlapping the stack case 20 in the vehicle longitudinal direction. Is also good.

  As shown in FIG. 1, the inlet member 52 is attached to an under cover 12b disposed below the stack case 20. The under cover 12b is a member that covers a lower portion of the front box 14, and is fixed to a body frame (not shown) of the fuel cell vehicle 12. The inlet member 52 is disposed below the lower surface of the stack case 20.

  The inlet member 52 penetrates the under cover 12b and is fixed. For this reason, the lower part (lower surface) of the inlet member 52 is exposed to the lower surface of the under cover 12b, and faces the road surface on which the fuel cell vehicle 12 runs. The upper part of the inlet member 52 is exposed inside the front box 14.

  As shown in FIG. 3, an air inlet 56 and an internal flow path 58 are formed in the inlet member 52. Specifically, the inlet member 52 includes an inlet forming member 60, a first flow passage forming member 62, a second flow passage forming member 64, a third flow passage forming member 66, and two seal members. 68a and 68b. The air inlet 56 is formed in the inlet forming member 60. The internal flow path 58 is formed by the inlet forming member 60, the first flow path forming member 62, the second flow path forming member 64, and the third flow path forming member 66.

  The introduction port forming member 60, the first flow path forming member 62, the second flow path forming member 64, and the third flow path forming member 66 are vertically stacked and connected. The first flow path forming member 62 is a hollow member, and is connected to an upper portion of the inlet forming member 60. The second flow path forming member 64 is a plate-shaped member, is superposed on the first flow path forming member 62, and is disposed between the first flow path forming member 62 and the third flow path forming member 66. Is sandwiched between.

  The third flow path forming member 66 is a hollow member, and is superposed on the second flow path forming member 64. The third flow path forming member 66 is fixed to the first flow path forming member 62 by a plurality of screws 68. The two seal members 68a and 68b are formed in a ring shape with a hollow cross section, and are provided between a flange 60a provided on the inlet forming member 60 and a flange 62a provided on the first flow path forming member 62. Will be retained. The under cover 12b is sandwiched between the two seal members 68a, 68b.

  The air introduction port 56 is a flow path for introducing air for ventilation from the outside, and is a circular opening in the present embodiment. The air inlet 56 may be a non-circular opening, for example, an elliptical opening, a rectangular opening, or the like. The inlet member 52 is disposed with the air inlet 56 facing downward. Therefore, the air inlet 56 faces the road surface on which the fuel cell vehicle 12 runs.

  Around the air inlet 56, a plurality of drain holes 70 that communicate the internal flow path 58 with the outside of the inlet member 52 are provided. The plurality of drain holes 70 are vertically penetrating the wall 57 forming the bottom of the chamber 58a. The plurality of drain holes 70 are formed in the inlet forming member 60. The plurality of drain holes 70 open on the upper and lower surfaces of the wall 57.

  The inlet forming member 60 is provided with a ring-shaped protrusion 72 that faces the plurality of drain holes 70 via the gap G below (directly below) the plurality of drain holes 70. The overhang portion 72 protrudes radially outward from a lower portion of the cylindrical peripheral wall portion 74 surrounding the air inlet 56.

  The internal flow path 58 has a cylindrical chamber 58 a adjacent to the air inlet 56 and a connection flow path 58 b that supplies air passing through the chamber 58 a to the tube member 54. In FIG. 3, the chamber 58a is located vertically above (directly above) the air inlet 56. The chamber 58 a is formed by an upper portion of the inlet forming member 60, a lower portion of the first channel forming member 62 and a lower portion of the third channel forming member 66.

  The inner diameter D1 of the chamber 58a is larger than the inner diameter D2 of the air inlet 56. The inner diameter D1 of the chamber 58a is larger than the inner diameter D3 of the tube member 54. The chamber 58a functions as a water storage (buffer) when water invades from the air inlet 56. The height of the chamber 58a is preferably larger than the inner diameter D2 of the air inlet 56, for example. Note that the height of the chamber 58a may be equal to or less than the inner diameter of the air inlet 56.

  The connection channel 58b communicates the chamber 58a with the channel 54a in the tube member 54. The inside diameter of the connection flow path 58b is substantially equal to the inside diameter D3 of the tube member 54. The connection flow path 58b is located vertically (directly above) the chamber 58a. The connection flow channel 58b is formed in a connection tube portion 66a provided above the third flow channel forming member 66. The air inlet 56, the chamber 58a, and the connection channel 58b are arranged coaxially in the vertical direction.

  The internal flow path 58 has a labyrinth flow path 78 in the chamber 58a. The labyrinth flow path 78 refers to a flow path that circulates in a cylindrical path in a meandering manner, for example, but the manner of the meandering is not particularly limited. The labyrinth flow path 78 is formed in a cylindrical shape along the weight direction (vertical direction). The inlet member 52 has at least one barrier plate 80 (barrier portion) forming a labyrinth flow path 78. In the present embodiment, the inlet member 52 has a plurality of barrier plates 80. Specifically, the plurality of barrier plates 80 include a first barrier plate 80a (first barrier portion) disposed above (directly above) the air inlet 56 so as to face the air inlet 56, and a first barrier plate. A second barrier plate 80b (second barrier portion) having an opening 80b1 formed at a position above (directly above) the first barrier plate 80a and facing the first barrier plate 80a.

  The first barrier plate 80a is provided integrally with the first flow path forming member 62 via a plurality of support portions 81. Therefore, the outer peripheral portion of the first barrier plate 80a is separated inward from the inner peripheral surface 58as forming the chamber 58a. The plurality of support portions 81 are provided at intervals in the circumferential direction. The first barrier plate 80a is formed in a disk shape.

  The outer diameter of the first barrier plate 80a is larger than the inner diameter of the air inlet 56. The outer peripheral portion of the first barrier plate 80a has a ring-shaped protruding portion 80a1 that protrudes while curving downward. The form of the first barrier portion facing the air inlet 56 is not limited to a plate-like form such as the first barrier plate 80a, but may be a thicker block-like form.

  The second barrier plate 80b forms an inner peripheral portion of the second flow path forming member 64. The second barrier plate 80b projects inward from an inner peripheral surface 58as forming the chamber 58a. The inner diameter of the opening 80b1 formed in the second barrier plate 80b is smaller than the outer diameter of the first barrier plate 80a. The center of the first barrier plate 80a and the center of the opening 80b1 are located on the same straight line in the vertical direction. Therefore, when viewed from vertically below, the first barrier plate 80a covers the entire opening 80b1.

  The inner peripheral portion of the second barrier plate 80b has an inclined portion 80b2 inclined downward toward the center of the opening 80b1. The inclination of the inclined portion 80b2 may be either a linear inclination or a curved inclination. The form of the second barrier portion having the opening 80b1 is not limited to a plate-like form such as the second barrier plate 80b, but may be a thicker block-like form.

  In the inlet member 52, the first to fifth constricted channels 78a to 78e are formed as the labyrinth channel 78 is provided. The first constricted flow path 78a is a flow path formed by the air inlet 56. The second constricted flow path 78b has a flow path width W1 in the vertical direction formed between the outer peripheral portion (ring-shaped protruding portion 80a1) of the first barrier plate 80a and the upper surface of the wall portion 57 constituting the bottom of the chamber 58a. It is a ring-shaped flow path having

  The third constricted flow path 78c is a flow path formed between the outer end of the first barrier plate 80a and the inner peripheral surface 58as forming the chamber 58a and having a flow path width W2 in the horizontal direction. The third constricted flow path 78c is composed of a plurality of flow path elements 78ce divided in a circumferential direction by a plurality of support portions 81.

  The fourth constricted flow path 78d is a ring-shaped flow path formed between the outer peripheral portion of the first barrier plate 80a and the inner end of the second barrier plate 80b and having a flow width W3 in the vertical direction. The fifth constricted channel 78e is a channel configured by the opening 80b1 of the second barrier plate 80b.

  Each of the first to fifth constricted channels 78a to 78e has a channel cross-sectional area that is equal to or larger than the channel cross-sectional area of the tube member 54. Therefore, the cross-sectional area of the labyrinth flow path 78 is equal to or larger than the cross-sectional area of the tube member 54 over the entire length of the flow path. For the third constricted flow channel 78c, the sum of the flow channel cross-sectional areas of the plurality of flow channel elements 78ce is the flow channel cross-sectional area of the third constricted flow channel 78c. It is preferable that each channel cross-sectional area of the first to fifth constricted channels 78a to 78e is, for example, 100 to 170% of the channel cross-sectional area of the tube member 54.

  In FIG. 1, the tube member 54 is disposed inside the front box 14. As the tube member 54, for example, a hose (flexible tube) is used. One end of the tube member 54 is connected to the ventilation opening 44 in an air-tight and liquid-tight manner. The other end of the tube member 54 is connected to the inlet member 52 in an air-tight and liquid-tight manner. The other end of the tube member 54 is located below one end of the tube member 54.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  During operation of the fuel cell stack 10, fuel gas is supplied from the fuel gas supply manifold 32a of the first end plate 26a to the fuel gas inlet communication hole. The fuel gas is introduced into the fuel gas flow path in the power generation cell 18 through the fuel gas inlet communication hole. Thereby, the hydrogen gas is supplied to the anode electrode constituting the electrolyte membrane / electrode structure.

  On the other hand, the oxidizing gas is supplied from the oxidizing gas supply manifold 30a of the first end plate 26a to the oxidizing gas inlet communication hole. The oxidizing gas is introduced into the oxidizing gas flow path in the power generation cell 18 through the oxidizing gas inlet communication hole. Thereby, the oxidizing gas is supplied to the cathode electrode constituting the electrolyte membrane / electrode structure.

  Therefore, in the electrolyte membrane / electrode structure of the power generation cell 18, the hydrogen gas supplied to the anode electrode and the air supplied to the cathode electrode are consumed by the electrochemical reaction in the electrode catalyst layer, and power is generated. .

  The fuel gas is discharged to the fuel gas discharge manifold 32b of the first end plate 26a through the fuel gas outlet communication hole. The oxidizing gas is discharged to the oxidizing gas discharge manifold 30b of the first end plate 26a through the oxidizing gas outlet communication hole.

  The cooling medium is supplied to the cooling medium inlet communication hole from the cooling medium supply manifold 33a of the second end plate 26b. The cooling medium is introduced into a cooling medium flow path between adjacent power generation cells 18. After cooling the electrolyte membrane / electrode structure, the cooling medium flows through the cooling medium outlet communication hole and is discharged to the cooling medium discharge manifold 33b.

  In this case, in the present embodiment, a ventilation mechanism 50 that ventilates the inside of the stack case 20 through the ventilation opening 44 that opens into the stack case 20 is provided. As shown in FIG. 3, the ventilation mechanism 50 includes an inlet member formed with an air inlet 56 for introducing air for ventilation from the outside, and an internal flow path 58 communicating the air inlet 56 and the ventilation opening 44. 52.

  Therefore, the air introduced from the air inlet 56 is supplied to the stack case 20 via the internal flow path 58. Therefore, the inside of the stack case 20 can be well ventilated, and the hydrogen gas concentration in the stack case 20 can be maintained at a certain concentration or less. In this case, the air introduced from the air inlet 56 flows outward below the first barrier plate 80a, and then flows between the outer peripheral portion of the first barrier plate 80a and the inner peripheral surface 58as forming the chamber 58a. Flows upward. Then, the air flows inward between the first barrier plate 80a and the second barrier plate 80b, flows upward through the opening 80b1 of the second barrier plate 80b, and flows into the tube member 54. .

  The internal flow path 58 has a labyrinth flow path 78. For this reason, even when foreign substances such as water, dust, mud, and pebbles are scattered toward the inlet member 52 when the fuel cell vehicle travels, the foreign substances are directed to the ventilation opening 44 side by the labyrinth flow path 78. Progress is suppressed. Therefore, it is possible to suppress foreign matter from entering the stack case 20 through the ventilation opening 44 as much as possible.

  In the present embodiment, the ventilation mechanism 50 has a tube member 54 having one end connected to the ventilation opening 44 and the other end connected to the inlet member 52. Therefore, the degree of freedom in the layout of the arrangement of the inlet members 52 can be improved.

  In the present embodiment, the inlet member 52 is disposed on the under cover 12b of the vehicle on which the fuel cell stack 10 is mounted, and the air inlet 56 opens on the lower surface of the vehicle (the lower surface of the vehicle body 12a). For this reason, it is possible to satisfactorily introduce the outside air and to prevent the hydrogen gas from leaking into the space (the front box 14 and the like) where the fuel cell stack 10 is arranged.

  In the present embodiment, the flow path cross-sectional area of the labyrinth flow path 78 is equal to or larger than the flow path cross-sectional area of the tube member 54 over the entire length of the flow path. Specifically, each of the first to fifth constricted channels 78a to 78e has a channel cross-sectional area equal to or larger than the channel cross-sectional area of the tube member 54. Thereby, air can be satisfactorily circulated from the air inlet 56 side to the tube member 54 side. Therefore, it is possible to prevent a decrease in ventilation capacity caused by providing the labyrinth flow path 78.

  In the present embodiment, the inlet member 52 has at least one barrier plate 80 that forms the labyrinth flow path 78, and has an inner peripheral portion or an outer peripheral portion of the at least one barrier plate 80 (the outer peripheral portion in the first barrier plate 80a, The inner peripheral portion of the second barrier plate 80b) is inclined or protruded downward. Since the barrier plate 80 is inclined or protruded downward, even if water flows in above the barrier plate 80, it can be smoothly drained downward by gravity. In particular, in the present embodiment, the second barrier plate 80b has the inclined portion 80b2. The angle θ (the angle with respect to a plane perpendicular to the axis of the inlet member 52) of the inclined portion 80b2 is set to an angle at which water does not accumulate even when the vehicle is required to be inclined (about 20 °). Accordingly, it is possible to prevent water from being accumulated in the second barrier plate 80b and being damaged by freezing or the like.

  In the present embodiment, the air inlet 56 opens downward, and the inlet member 52 has a plurality of barrier plates 80 forming a labyrinth flow path 78. The plurality of barrier plates 80 are disposed opposite the air inlet 56 and disposed above the air inlet 56, and the first barrier plate 80a is disposed above the first barrier plate 80a and faces the first barrier plate 80a. And a second barrier plate 80b formed with an opening 80b1 that opens at the position where the second barrier plate 80b is formed.

  For this reason, for example, when the amount of water is small such as when traveling in rainy weather, as shown in FIG. 4, the water scattered in a substantially vertical direction from the air inlet 56 toward the chamber 58a enters the back side by the first barrier plate 80a. Is blocked. Water scattered obliquely from the air inlet 56 toward the chamber 58a passes between the inner peripheral surface 58as forming the chamber 58a and the first barrier plate 80a, but is further reduced by the second barrier plate 80b. Intrusion into the back side is also prevented. For this reason, infiltration of water into the back side (the tube member 54 side) can be favorably suppressed. Further, since the ring-shaped projection 80a1 projecting downward is provided on the outer peripheral portion of the first barrier plate 80a, it is easy to prevent water from entering above the first barrier plate 80a.

  In the present embodiment, the inlet member 52 is provided with a plurality of drain holes 70 around the air inlet 56 that communicate the internal flow path 58 with the outside of the inlet member 52. For this reason, for example, at the time of a large amount of water such as during high-pressure car washing, water is discharged from the chamber 58a through the drain hole 70 as shown in FIG. Penetration is suppressed. That is, water accumulates in the chamber 58a depending on the state of the inflow water amount V1> the outflow water amount V2, and the water level (the height of the water surface Lv) rises. As the water level rises, the outflow from the drain hole 70 also increases. For this reason, the outflow water amount V2 increases, and the water level is balanced with the inflow water amount V1 = the outflow water amount V2. Thereby, it is possible to suppress the water level in the inlet member 52 (the internal flow path 58) from rising too much.

  Since the overhang portion 72 is provided vertically below the drain hole 70, the water scattered from below the drain hole 70 vertically upward is rebounded by the overhang portion 72. This effectively prevents water from entering the chamber 58 through the drain hole 70.

  FIG. 6 shows a test result for confirming the effect (water level adjusting function) of the drain hole 70. The magnitude relationship between the inflow water amounts Va to Vd is Va <Vb <Vc <vd. As shown in FIG. 6, initially, the water level in the chamber 58a rises regardless of the amount of water, but thereafter, the water level balances regardless of the magnitude of the inflow water amount.

  As shown in FIG. 7, a mesh member 84 may be provided in the air inlet 56. The mesh member 84 is provided so as to cover the air inlet 56. The mesh member 84 is, for example, a part formed integrally with the introduction port forming member 60. The mesh member 84 may be a component fixed to the inlet forming member 60.

  When such a mesh member 84 is provided, even if solid foreign matter such as pebbles scatters toward the air inlet 56, the solid foreign matter collides with the mesh member 84. Thereby, it is possible to preferably suppress solid foreign matter such as pebbles from entering the air inlet 56.

  In the above description, the example in which the inlet member 52 is connected to the stack case 20 via the tube member 54 and is disposed on the under cover 12b has been described, but the inlet member 52 may be disposed at another location. Good. For example, the inlet member 52 may be arranged on the lower panel 20Lw of the stack case 20. In this case, the tube member 54 is omitted, and, for example, the connection tubular portion 66a is inserted into and fixed to the ventilation opening 44. In addition, the peripheral wall portion 59 between the two flanges 60a and 62a of the inlet member 52 may be inserted into the ventilation opening 44, and the lower panel 20Lw may be sandwiched between the two seal members 68a and 68b.

  The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... In-vehicle fuel cell stack 18 ... Power generation cell 19 ... Laminated body 20 ... Stack case 44 ... Ventilation opening 50 ... Ventilation mechanism 52 ... Inlet member 54 ... Tube member 56 ... Air inlet 58 ... Internal flow path 58a ... Chamber 70 ... Drain hole 78 ... Labyrinth flow path 80 ... Barrier plate 80a ... First barrier plate 80b ... Second barrier plate

Claims (9)

A power generation cell that generates power by an electrochemical reaction between a fuel gas and an oxidizing gas, the vehicle fuel cell stack including a plurality of stacked bodies, and the stacked bodies are housed in a stack case,
A ventilation mechanism that ventilates the stack case through a ventilation opening that opens into the stack case,
The ventilation mechanism has an air inlet for introducing air for ventilation from the outside, and an inlet member formed with an internal flow passage communicating the air inlet and the ventilation opening,
Said internal passage, have a labyrinth flow path,
It said labyrinth flow path, Ru is formed into a cylindrical shape along the direction of gravity,
An in-vehicle fuel cell stack characterized by the above-mentioned. The fuel cell stack for a vehicle according to claim 1,
The ventilation opening is provided at a lower portion of the stack case,
An in-vehicle fuel cell stack characterized by the above-mentioned. The fuel cell stack for a vehicle according to claim 2,
The ventilation mechanism has a tube member having one end connected to the ventilation opening and the other end connected to the inlet member.
An in-vehicle fuel cell stack characterized by the above-mentioned. The fuel cell stack for a vehicle according to claim 3,
The inlet member is disposed on an undercover of a vehicle on which the on-vehicle fuel cell stack is mounted, and the air introduction port opens on a lower surface of the vehicle.
An in-vehicle fuel cell stack characterized by the above-mentioned. The fuel cell stack for a vehicle according to claim 3 ,
The flow path cross-sectional area of the labyrinth flow path is equal to or larger than the flow path cross-sectional area of the tube member over the entire length of the flow path.
An in-vehicle fuel cell stack characterized by the above-mentioned. The vehicle fuel cell stack according to any one of claims 1 to 5 ,
The air inlet is open downward,
The inlet member has at least one barrier plate forming the labyrinth flow path,
An inner peripheral portion or an outer peripheral portion of the at least one barrier plate is inclined or protruded downward.
An in-vehicle fuel cell stack characterized by the above-mentioned. The vehicle fuel cell stack according to any one of claims 1 to 5 ,
The air inlet is open downward,
The inlet member has a plurality of barriers forming the labyrinth flow path,
The plurality of barrier portions are a first barrier portion disposed above the air introduction port so as to face the air introduction port, and an opening is provided at a position above the first barrier portion and facing the first barrier portion. And a second barrier portion having an opening formed therein.
An in-vehicle fuel cell stack characterized by the above-mentioned. The vehicle fuel cell stack according to any one of claims 1 to 5 ,
The air inlet is open downward,
The inlet member is provided around the air inlet with a plurality of drain holes communicating the internal flow path and the outside of the inlet member.
An in-vehicle fuel cell stack characterized by the above-mentioned. An in-vehicle fuel cell stack according to any one of claims 1 to 8 ,
The air inlet is provided with a mesh member,
An in-vehicle fuel cell stack characterized by the above-mentioned.

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